That looks a good setup, bwhli. I have looked at stuff such as laptop stands, but the only problem is where to place extra stuff. I have a Duet 2 as my audio interface plus an external hard drive where all my streaming Kontakt and Spectrasonics sample libraries are located, so placing them on the floor isn't the ideal spot.
With your Yamaha piano, did you connect jack-to-jack leads to the PA just in case the computer crashed, etc?
I'm gonna be posting my setup photos from rehearsals last week for a gig that's on in Melbourne I'm involved in this week where I'm using MainStage, and it's turned out a treat.